JPH04354180A - Manufacture of multilayer printed wiring board - Google Patents

Abstract

PURPOSE:To provide a multilayer printed wiring board having a non-through connection through hole in easy steps. CONSTITUTION:In a method for manufacturing a multilayer wiring board having a nonthrough connection through hole 12, nonplated resin 5 such as Teflon, etc., is filled in partial hole of an inner layer, multilayers are formed, a through hole is formed at the board, normally through hole-plated, thereby forming a blind viahole (non-through connection through hole 12) to be connected only between the inner layer and an outer layer. Thus, an inner viahole 11 is easily formed in the inner layer.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a multilayer printed wiring board having non-through connection through holes.

0002

2. Description of the Related Art A conventional technique will be explained with reference to FIGS. 13 to 15.

FIG. 13 shows an inner via hole 1 in the inner layer.
1. Blind via hole 14, 14 between outer layer and inner layer
This is an example of a four-layer printed wiring board. The through holes 11 and 14 are both non-penetrating through holes.

[0004] In this printed wiring board, the inner layer core material 4 is formed in the same manner as a double-sided through-hole printed board, laminated and pressed to become a multilayer material, and then blind via holes 14, 14 of the outer layer insulating layer 6a are formed. The feature is that the part is formed by stopping the drill midway through the board without penetrating it. This printed wiring board has an inner via hole 11, blind via holes 14, 14, and a through hole (
(not shown), it is very useful with a large degree of freedom in design.

However, this method requires a difficult technique of stopping the drill midway, which requires precision in the thickness direction of the board, so there is a problem in that it cannot be manufactured without special equipment. Moreover, since it is impossible to stack the substrates and process them, there is a drawback that productivity is extremely low.

FIG. 14 shows an example of a four-layer printed wiring board having blind via holes 15, 15 between the inner layer and the outer layer. 6 is an outer layer material, and 6b is an inner insulating layer formed after lamination pressing. Since this printed wiring board is formed by laminating two outer layer materials 6 made of double-sided through-hole printed wiring boards, there is no need for special equipment for forming blind via holes 15, 15, and it is possible to use ordinary double-sided boards. It is possible to do this by laminating and pressing in the process. Therefore, there is no productivity problem as mentioned above.

However, although blind via holes 15, 15 and through holes (not shown) are possible in this printed wiring board, inner via holes (11
, see FIG. 13) is impossible.

FIG. 15 shows an inner via hole 1 in the inner layer.
This is a 4-layer printed wiring board with 1. This printed wiring board can also be produced using the double-sided board process, as described above.
There are no productivity issues. However, with this technique, although the penetrating through hole 16 and the inner via hole 11 can be formed, the blind via hole (14 or 15, see FIG. 13 or 14) cannot be easily formed. If an attempt is made to form a blind hole with this configuration, a problem similar to that shown in FIG. 13 will arise.

[0009]

[Problems to be Solved by the Invention] As mentioned above, the conventional example shown in FIG. 13 requires special equipment and has problems in productivity, and in FIG. It is not possible to connect between layers, and Figure 1
No. 5 has its own problems, such as the impossibility of forming a blind via hole to connect the outer layer and the inner layer.

In view of the above-mentioned problems, the present invention provides a manufacturing method by which a multilayer printed wiring board having non-penetrating connection through holes can be easily obtained.

[0011]

[Means for Solving the Problems] In a method for manufacturing a multilayer printed wiring board having non-penetrating connection through holes, some of the holes in the inner layer are filled with a non-plating resin, and after multilayering, the non-plating resin in the inner layer is filled with a non-plating resin. The present invention is characterized in that a through hole passing through a portion filled with plating resin is formed and through hole plating is performed to form a non-penetrating connection through hole in the through hole portion.

0012

[Operation] As mentioned above, the present invention forms a hole that penetrates the wiring board after multilayering, but inside the hole there is a resin part such as Teflon that is not plated in the through-hole plating process. By applying normal through-hole plating to it, the resin part is not plated, and even if it is a through hole, it does not become a through hole, and a non-through connection through hole that easily connects the outer layer and the inner layer is formed. can. Furthermore, inner via holes can also be easily formed in hole portions that are not filled with resin in the inner layer before lamination.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 show a multilayer printed wiring board made according to an embodiment of the present invention. FIG. 1 shows an example of a four-layer board, and FIG. 2 shows a six-layer board. Although not shown in the drawings, it is also possible to apply the present invention to printed wiring boards with a higher number of layers.

FIG. 1 and FIGS. 3 to 12 showing the manufacturing process
One embodiment will be described in detail.

FIG. 3 shows the state of the inner layer material before processing. The inner layer material 4 is usually a glass cloth epoxy material, and copper foils 1 are usually formed as conductors on both sides thereof.

Next, as shown in FIG. 4, N is applied to the inner layer material 4.
Holes 8a and 8b are machined by C drilling or the like. Here, 8a is a hole for filling resin in the non-penetrating connection portion, and 8b is a hole for an inner via hole.

In FIG. 5, the hole 8a is filled with non-plating Teflon resin 5, and a part of the upper surface of the Teflon resin 5 is chemically treated with a special chemical called "tetra etch" so that plating is formed on the upper surface of the Teflon resin 5. After performing this, normal through-hole plating is performed to form the shape shown in FIG. 6, and the holes 8b are plated. Plated conductor 2 is typically copper.

Then, the inner layer material 4 shown in FIG. 7, which is etched and patterned, is obtained by a so-called subtractive method. After the through hole 10 in the hole 8b is laminated and pressed, the inner via hole 11 (see FIG. 1 and FIG. 9 described later)
This is the part where it becomes.

As shown in FIG. 8, the inner layer material 4 is coated with prepreg (B stage (semi-cured state) on glass cloth) on both sides.
impregnated with resin (here epoxy)) 7,
Then, a single-sided plate made of an outer layer material 6 on which copper foil 1 is formed is arranged on both sides thereof, and lamination pressing is performed. After lamination pressing, the result is shown in Figure 9.

The outer layer material 6 is usually glass epoxy, but
Since the outer layer material 6 is also formed by laminating and pressing the prepreg 7, in some cases, the prepreg 7 and the copper foil 1
Lamination pressing may also be performed. The portion 11 is the inner layer material 4
Resin is embedded inside the through hole 10 by laminating press, and the through hole itself is embedded in the multilayer board, and is called an inner via hole.

After lamination, as shown in FIG. 10, a through hole 9 is provided in a portion where a non-through connection is to be made. This is also done using NC drilling, etc. Then, in order to make a non-through connection, through-hole plating is performed, but unlike the case of the inner layer material described above, this time, normal through-hole plating is performed without performing the "tetra etch" treatment.

As a result, as shown at 13 in FIG. 11, the plating 3 is not attached to the area where the Teflon resin 5 is located.
When this is patterned by the subtractive method as described above, a non-through connection through hole 12 is formed in the portion 9 as shown in FIG. 12, and the structure shown in FIG. 1 is obtained.

FIG. 2 shows a six-layer board in which two inner layer materials 4 are used as described above. 6a is a part where the outer layer material 6 and the prepreg 7 of the single-sided board or the prepreg 7 are formed by lamination press, and 6b is a part where the prepreg 7 arranged between the inner layer materials is formed by lamination press.

[0024] The same method can be applied to even higher multilayer cases.

As described above, a portion of Teflon resin 5, etc., which is not plated in the normal through-hole plating process, is formed inside the through-hole at the part where it is not desired to be connected by through-hole plating, and then normal through-hole plating is performed. Therefore, the portions such as the Teflon resin 5 are not plated, and even if a through hole is formed, it does not become a through hole, but becomes a non-through connection through hole 12.

Therefore, according to this example, the non-through connection through hole 12 between the outer layer and the inner layer, which has the same function as the blind via hole that connects between the outer layer and the inner layer, and the inner via hole 11 that connects between the inner layer and the inner layer. Both of these can be formed, and the through holes can be formed like a normal double-sided board, no special equipment is required, and the holes can be made by stacking the substrates like a normal double-sided board.

[0027]

[Effects of the Invention] As described above, the present invention enables non-penetrating connection through-holes that connect insulating layers formed from prepregs by laminating press in a multilayer printed wiring board to be formed using a special method in which a drill is stopped in the middle of the board as in the conventional method. It can be easily formed by drilling a through hole like a normal through hole without using any special method. Along with this, it is possible to overlap the boards and make holes. Work efficiency is greatly improved, such as not having to drill holes on both sides one by one, which is advantageous in terms of delivery time and cost, making it extremely useful.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the structure of a multilayer printed wiring board according to an embodiment of the present invention.

FIG. 2 is a sectional view showing another structural example.

FIG. 3 is a cross-sectional view illustrating an example of the manufacturing process shown in FIG. 1;

FIG. 4 is a sectional view illustrating an example of the manufacturing process.

FIG. 5 is a cross-sectional view illustrating an example of the manufacturing process.

FIG. 6 is a cross-sectional view illustrating an example of the manufacturing process.

FIG. 7 is a cross-sectional view illustrating an example of the manufacturing process.

FIG. 8 is a cross-sectional view illustrating an example of the manufacturing process.

FIG. 9 is a cross-sectional view illustrating an example of the manufacturing process.

FIG. 10 is a cross-sectional view illustrating an example of the manufacturing process.

FIG. 11 is a cross-sectional view illustrating an example of the manufacturing process.

FIG. 12 is a cross-sectional view illustrating an example of the manufacturing process.

FIG. 13 is a sectional view showing an example of a conventional structure.

FIG. 14 is a sectional view showing another conventional structure example.

FIG. 15 is a sectional view showing still another conventional structure example.

[Explanation of symbols]

4 Inner layer material 5 Teflon resin 6 Outer layer material 11 Inner via hole 12 Non-through connection through hole

Claims (1)

[Claims] 1. A method for manufacturing a multilayer printed wiring board having non-penetrating connection through holes, in which some holes in an inner layer are filled with a non-plating resin, and after multilayering, the inner layer is filled with the non-plating resin. 1. A method for manufacturing a multilayer printed wiring board, comprising forming a through hole passing through the through hole portion and performing through hole plating to form a non-through connection through hole in the through hole portion.